This invention relates to a cage for transporting fish fingerlings under water from an upstream hatchery down a river to a release point near the ocean without removing the fish from the water, and to a method of using such a cage.
Transporting ocean cycle fish fingerlings from an inland hatchery to the ocean is currently accomplished in two ways. One way is to pump the fish into a river and allow them to follow the river's current downstream. However, predators, such as birds, larger fish and seal lions, gather around where the fish are pumped into the river. The fish become disoriented by the pumping process and a high percentage of them are immediately lost to these predators. In addition, when the remaining fish reach dams they pass through the turbines which kills even more. The second method is to pump the fish into a tank truck and drive them to a release point and then pump them out of the tank truck into the river. However, the fish again are disoriented when pumped back into the river and are easy prey for the natural predators. This is aggravated by the fact that hatchery fish are fed from above in the hatchery and when pumped out of the tank truck the fish swim to the surface looking for food.